Starter jaw meshing mechanism



R. M. HEIN-rz 2,513,937

2 Sheets-Sheet 1 STARTER SAW MESHING MECHANISM July 4, 195o Original Filed Dec. 6, 1944 ATTORNEY July 4, 1950 R. M. HEINTz 2,513,937

STARTER sAw MESHING MECHANISM original Filed Dec. 6, 1944 2 sheets-sheet 2 IN VEN TOR.

RALPH M HEINTZ mum Patented July 4, 1950 Ralphy M. Heintz, Gleveland, Ohio, assignon to.t Jack dlrv Heintz Precision Industries,y I1`1 c` (lleven-Q.y

land, Ghia,I a. corporation ofJD'elavvare Original application December-76, 1944; Sem'al No.

566,871. Dividedand this 194s, serial No. 38,572

zclaiwips.n (.01. 12s- 179) 'Ihisn invention relatesyvftoajaw meshing mecha.

nismg for aircraft engine; starter .and the. like and is a. division, of the co-pending applicationA ferpatent in the: narnefct'Ralph- M, Heintz, seni-a1 No.v 56!5;- 7,11 forl Starter` Jaw Meshing Mechanism, -led llecemleer6.,v 1944, newA abancloned.

'I jhey generallobject of the, invention isA to pro.- Videan. improved jawmeshing mechanism for automatieally.Y extending., a; starter jaw. and engagingy it Withtheengine-,tothe started. More..

specifically; the object of-the invention. is to pro-l Vdf'meall iol@ P9tV1y and. rapidly extend* ing tl'ievstartery jawasitbegins to rotate soythat it will always,enter;l into.. complete engagement with, the: engjnein. a more; satisfactory manner thanI in4 cern/en.tienalf.v arrangements. In order to accomplish these objectives it is` a further object. to provide a spring for extending the Starter Jatfflntc. mesh withY the enginer jaw and a nut having. frlctlcnal. enf-5.agement with the 'Starter jaw. in ccrnbinatlcnwltll a threaded Shaft rotatable Within the nut for controlling the ex.- tension of the starter jaw. i

The lntentlen will. ncaav be, deecrihed, in cen..-

necnon with the accompanying d.ratones,` in.

which v Figure l is a fragmentary, View in eectlcntalsen.

along line. I-fl, or Figure. 2:, s howirnigv allpr'eferred,

ferne cfv jaw meshing. mecha ern, constructed according to the pre entlnventlcn, the law. lee-1 ing in retracted. pcsltlen; ani.

Figure 2 isa. View. in rear enslelevatlen, partly in section, showing the gearing connection from the motor. to, the. tralnf..

Referring. mere. particu' rlr te. the dra.,titlesl,Y

the.. starter l an electric. meter. 2. driving a, f

gear train. which. nltnnately. eredncee natation.

of a gear Snert, 31er ef internal. fine eear l- All tleeelenrents ct; tnleeear do, nct appear the flrawlna ittelne.- necesr sary only te. understand.; thatA the. rire gear 4; is motor driven. The sun gear slikajfwt` 3 'includes an. integral. een eser, 5 meen with. a plurality cf nlanetgeare planet 'terrier l. The. planet gears: preterablr, nnmleea. with a, ring. gear. comprising. aplnrality er inter nalltr tcctnea clutch plate l.. a1 terrine. release plate etacls. assembly, 8; 'line catch. assembly t is similarln general ter that. Shown. and-decente@ in my.. Patent Nc,... 2.,3ll.3;,i3..7 Ralph; lelnta. issued; December 1.,.' 19512,. and: in Patent Ne! 2,211.1.6s4lll- Ralph; ieeueefebrnary 3,. 1942, whereintleeeeeeallea eine: gear rnavf be considere@ etatlenan in the starter armieaticn July 1.4,@

2l housing so, asV todlruiyre, the planet carrier whenA the sup gea.; rotates i The planetufnlrl partY thereof: a sleeve, I

l a tearingt t. anellhavine internal Spline grooves.

Il carrying a. member 12,thel1'atter.. beine externally Splnerito flttnesplinesll, The jaw f member l2. le'tlrereby rctatecl ferl enelne crank..-

integrally connectedy with the ring gear 4 so turn rotates much more slowly than the motor 2. As shownin Figure-Y2, the lmotor 2 has an output driving gear 53 that mesheswith a larger gear 54 that is-mounted on the sameshaft to rotate a smaller gear 55 that meshes with a larger gea-r 55; Gearl 56=-is carried bythe same shaft as a planetaryfgear 51y in the planetary gear carrier 58; Planetary gear 51 meshes with the internal ring gear 4.

The s un gear shaft 3. ist mounted in bearings I3= and: |41 andl is provided at its. outer end with spiralL threads I5 ofy high pitch, the threads making an angle. ofL approximately 45 degrees` f outer enel4 bearing against, theseat 2u, to.v con.n stantly. urge` the jawI member toward extended position. f

The-jaw, member I2f is provided. with a.. central conical surface 24 receiving a cone nut 2 5l havine; enter cenlcal externally flnted end 2.6- lcearins thereagallastI asy shown l5, andI le provided with. an anertured abutment Washer 2.1- A. J'aw return. belt 30; rasseethrcugh the.; a cement. 2t anev is. prox/1aed with. a had.

3| fer tra tine the cene nut. and; Jaw member after a etartlne` ce.eration:l under the action cf- 3 within the; 22:5. causes the. latter to. 'move l alells'tlle Shaft as a. nut. asleng aeit .is-restrained from; rotatio with the shaft by, friotional enr-- Sagem/ent; Wrtl-.t thev jaw member V rI-he cone nut A 25 is internally threaded te. nt. thespiral threads The spring 1 l' .positive rotational Apower drive. `the travelling cone 25 is spirally threaded on` 2| causes the jaw member to follow the nut 25 as the latter is extended on the shaft 3 until the jaw member becomes engaged and fully seated in its comating jaw member I2' on the engine. The outward travel of the nut 25 will then cease as soon as it loses its fricticnal engagement with the jaw member so that it is free to rotate with the shaft 3. A nut 33 on the bolt 3c serves both as an abutment for the spring 32 and as a stop to limit excessive outward movement of the parts inasmuch as it will ultimately come to bear against the end 34 of the shaft 3. The opposite end 35 of the shaft 3 constitutes' a similar stop for the parts in their return movement so as to leave a clearance between the jaw member I2 and the starter housing when the jaw member is fully retracted.

The planetary gear ratio is such that the difference in rotational speeds between the sun gear and the planet carrier is much greater than the speed of sleeve I with respect to the housing, thereby providing a novel and rapid automatic means of traverse for extending the jaw member'. When the starter motor begins to turn, the rotation of the shaft 3 screws the cone nut 25 outwardly against the compression of spring 32 from its position shown in the drawings to a position Where it is free to. slip within the jaw member I2 after the latter has engaged itself with the comating jaw I2 on the engine to be cranked.. vIt will beI appreciated that asv soon as slippageoccurs between the cone nut 25 and the jaw member l2 the cone nut will merely rotate with the sun gear shaft 3 Without extending it self further, clearance being provided between the shaft end 34 and the stop nut 33 when the jaw is seated.

When the engine fires-while the starter is still cranking, the jaw member I2 will experience the usual ratchet action by the rapidly revolving engine jaw, causing the jaw I2 to reciprocate in and out on the cone lnutagainst the'compression of the jaw spring 2|. When they starter is switched off and stops revolving the jaw return spring 32 through the reaction of the bolt head 3| on the abutment` washer 21v causes the cone nut to spin down to followrthe inward motion of the jaw I2 each time the latter is cammed inwardly away from the cone nut by the revolving teeth on the engine jaw. kIn this manner the `jaw I2 is finally returnedclear of the engine jaw I2 where it is held by the action of the jaw return spring whichfexerts a force considerably in excess of the jaw spring 2|.' Vibration of the parts tends to cause further slippage between the cone nut and the jaw I2 to finally return the jaw to' its fully retracted position shown in Figure 1. Y

Through'the appropriate" reduction gear train andthe standard lfriction* torque release plate stack the motor armature shaft is the direct and only positive drive for 'rota-ting the Starter jaw from those of the prior art which use a travelling nut as the jaw extension means as well as the In my device the extension drive shaft 3. vThe outer ends of 4 cone 24 and the starter jaw have complementary surfaces to form a cone clutch which is only effective by reason of the coil spring 2| under greatY compres-sion between a retaining flange on the `inner end of the cone and a shoulder toward the forward end "ofthe starter jaw.

Coil spring 2| has two verydenite important functions. First, it effects frictional engagement inthe cone clutch without which a rotation of the spiral threads I5 would merely carry the.

cone along with it without effecting any relative rotation therebetween. It is only by reason of the expansive force of spring 2| that a rotational drive and longitudinal extension of the cone is effected. It must also be borne in mind that spring 2|, being initially under compression,

i to effect uncontrolledr jaw mesh'.y When the,

would force the starter jaw outwardly if it were not confined and prevented by the cone clutch. As the cone 25 is driven outwardly, through the spiral threads and the cone clutch made effective by spring 2|, the cone drags spring 2| along with it. However, it is the expansive force of spring 2| that,` effects jaw mesh. As a matter' of fact, thev cone 25 travels slightly further outwardly after the jaw mesh and spring 2| not only effects but maintains jaw mesh as the cone travels further,

to disengage the cone clutch.

When the engine starts, the engine jaw overrides the starter jawand kicks the latter back against the action of Spring 2| Which then acts to re-engage the cone clutchto prevent spring 2| starter motor is de-ene'rgized, the separate spring 32 exerts a force on the cone causing it to slip in the cone clutch and spiral inwardly to bring it and the starter jaw into fully retracted position.

From the foregoing it .will be seen that the rotational drivel of the Avstarter is effected by a means separate and independent of that for ex-r tending and retracting the starter jaw. Moreover, the spring 2| is,y the means for jaw.mesh and also for establishing an extending' drive for the cone.

I claim:

1. In `an engine starter having a planetary reduction gearing unit comprising a sun gear driving shaft and a driven planet carrier,v an extendable jaw member splined in said4 planet carrier, a jaw spring having a fixed abutment in said starter and arranged to urge said jaw member to its extended position, a conical friction surface in said jaw member, a cone nut having a vconical friction surface adapted to engage said jaw member, a threaded portion on said sun gear shaft rotatable within said nut to extend v'same to allow said jaw spring to extend said I.

jaw, a recess in said sun gear shaft,`a jaw return bolt within said recess and bearing against said cone nut, and a jaw return spring within said recess` and acting on said vbolt with a force superior .to said jaw spring to retractsaid'ynut 'and said jaw member 4upon'|` cessation of rotation of the jaw member.

. 2*..In an engine: starter' having 'a lplanetary;` reduction gearing unit comprising a sun gear driving shaft and drivenplanet carrier, an ex.` l tendable jaw member splined in said planet car. rier, a,` jaw s-pring having'a fixed abutment inv said starter andarrangedto urge said jawhmember to its extendedposition, a conical friction surface in said jaw member, a cone nut having a conical friction surface adapted to engageI said y jaw member, a threaded portion on said sun gear j shaft rotatable within said nut'to extend same lto allow said jaw sprin'gto extendsaid'jaw, 'a' vrecess in said sun gear shaft, a jaw return bolt Within UNITED STATES PATENTS said recess and bearing against said cone nut, Number Name Date and a jaw return spring within said recess and 1 868 346 Chilton g July 19 1932 acting on said bolt with a force superior to said 2303637 Hemtz Dec 1 1942 jaw spring to retract said nut and said jaw member upon cessation of rotation of the jaw member. FOREIGN PATENTS RALPH M. HEINTZ- Number Country Date 2,61 Fn .,194 REFERENCES CITED 87 1 ra ce Feb 16 2 The following references are of record in the 10 file of this patent: 

